package leetcode._080;

/**
 * title: 80 Remove Duplicates from Sorted Array II
 *
 * Given a sorted array nums, remove the duplicates in-place such that duplicates appeared at most twice and return the new length.
 *
 * Do not allocate extra space for another array, you must do this by modifying the input array in-place with O(1) extra memory.
 *
 * Example 1:
 *
 * Given nums = [1,1,1,2,2,3],
 *
 * Your function should return length = 5, with the first five elements of nums being 1, 1, 2, 2 and 3 respectively.
 *
 * It doesn't matter what you leave beyond the returned length.
 * Example 2:
 *
 * Given nums = [0,0,1,1,1,1,2,3,3],
 *
 * Your function should return length = 7, with the first seven elements of nums being modified to 0, 0, 1, 1, 2, 3 and 3 respectively.
 *
 * It doesn't matter what values are set beyond the returned length.
 * Clarification:
 *
 * Confused why the returned value is an integer but your answer is an array?
 *
 * Note that the input array is passed in by reference, which means modification to the input array will be known to the caller as well.
 *
 * Internally you can think of this:
 *
 * // nums is passed in by reference. (i.e., without making a copy)
 * int len = removeDuplicates(nums);
 *
 * // any modification to nums in your function would be known by the caller.
 * // using the length returned by your function, it prints the first len elements.
 * for (int i = 0; i < len; i++) {
 *     print(nums[i]);
 * }
 */

/**
 * <a>https://leetcode.com/problems/remove-duplicates-from-sorted-array-ii/</>
 * @author chengfangming
 * 还是和之前一样，把数向前以前移动，但是需要记录前面已经有几个数相同了，
 * 当前数数值的最后一个值与下一个数比较
 *  [0,0,1,1,1,1,2,3,3]
 * 现在是0
 *
 */
public class Solution {
    public int removeDuplicates(int[] nums) {
        int length = nums.length;
        if (length == 0) {
            return 0;
        }
        int lastIndex = 0;
        int countNum = 1;
        int countSameNum = 1;
        for (int i = 1; i < length; i++) {
            if (nums[lastIndex] == nums[i]) {
                if (countSameNum < 2) {
                    nums[lastIndex + 1 ] = nums[i];
                    countNum++;
                    lastIndex = countNum - 1;
                }
                countSameNum++;
            } else {
                nums[lastIndex + 1] = nums[i];
                countNum++;
                countSameNum = 1;
                lastIndex = countNum - 1;
            }

        }
        return countNum;
    }
}
